含铝复合推进剂分布燃烧数值模拟

Numerical simulation of distributed combustion of the aluminized composite propellant

为研究发动机内含铝复合推进剂以及铝的燃烧,基于FLUENT软件,应用EDC模型和颗粒表面反应模型,建立了固体火箭发动机内流场两相流分布燃烧模型,对AP/HTPB/Al复合推进剂固体火箭发动机内流场进行了数值计算。计算结果表明,与表面燃烧相比,铝的燃烧导致发动机内出现了延长的燃烧区域,铝燃烧贯穿整个发动机燃烧室,形成分布燃烧;延长的燃烧区域导致发动机内流场分布不均匀,燃烧室是非等温的,温度由燃面附近的2600 K增长到3600 K,燃烧室核心区域温度约为3200 K;铝燃烧消耗的同时生成其他产物,也导致燃烧室内燃气组分和密度的分布不均匀;铝的燃烧是一个复杂的物理化学过程,对发动机内流场有着重要影响,颗粒相始终贯穿整个发动机,最终从喷管喷出。

For the research of combustion and flow of aluminized composite propellants and multiphase combustion of aluminum particles in the rocket motor,the numerical simulation of aluminized composite propellants was carried out. Based on the EDC combustion model and particle surface reaction model in FLUENT software,a two-dimensional and two-phase distributed combustion model of aluminized composite propellants was established according to the combustion theory of aluminum.The computing fluid filed was used to simulate the reacting flow in a solid rocket motor with AP/Al/HTPB propellant. The result shows that the relatively slow combustion rate of aluminum can result in an extended combustion zone in the chamber rather than a thin reaction region. The presence of the extended combustion zone results in the combustor flow field being far from isothermal,and the chemical composition being far from uniform.The temperature in the chamber increases from about 2600 K at the propellant surface to about 3600 K in the combustor,whereas the temperature is 3200 K in the core.The combustion of aluminum is a complex physical and chemical process,which has a great impact on the engine flow field.Particle phase is maintained throughout the entire engine and these particles are finally ejected out of the nozzle.